Predictors of Major Adverse Limb Events after Infrainguinal Bypass in Patients with Diabetes

Diabetes mellitus is a major risk factor for peripheral artery disease (PAD). The association of diabetes with major adverse limb events (MALE) after lower extremity revascularization (LER) remains controversial as patients with diabetes are often analyzed as a homogenous group. This study examines the impact of insulin use and glucose control on the outcomes of infrainguinal bypass. Our hypothesis is that insulin therapy and hemoglobin A1c (A1c) are predictors of MALE and might be used to stratify outcomes in of LER in patients with diabetes. The Vascular Quality Initiative (VQI) database for infrainguinal bypass (2007-2021) was reviewed. Patients with diabetes undergoing bypass for PAD were included. Patients on dialysis or with kidney transplant were excluded. The characteristics and outcomes of patients with insulin requiring diabetes mellitus (IRDM) were compared with patients not requiring insulin (NIRDM). A total of 9,686 patients with diabetes (56% IRDM) underwent bypass. Patients with IRDM were significantly younger than patients with NIRDM and more likely to be female, African American, and Hispanic. After a mean follow-up of 427 days post-operation, patients with IRDM had significantly lower primary patency and higher major amputation, MALE, and mortality. (Table) Regression analyses demonstrated that insulin use, but not A1c, was independently associated with higher risk of MALE (HR = 1.17 [1.06-1.29]) and mortality (HR=1.28 [1.16-1.43]). Prevalent insulin use, but not the degree of A1c control, is a significant predictor of MALE and survival after infrainguinal bypass and should be used to stratify the outcomes of LER in patients with diabetes.